1. Field of the Invention
The invention relates to an active matrix substrate inspecting method, an active matrix substrate, a liquid crystal device and an electronic apparatus. In particular, the invention relates to techniques for inspecting a type of active matrix substrate in which a digital data-line driver, i.e., a driver in which a digital signal is input and converted from digital to analog form to output an analog signal for driving data lines, (hereinafter referred to as a "digital driver") is formed on the substrate.
2. Description of the Related Art
In recent years, research has been conducted on an active matrix substrate with a built-in driver in which driving circuits (drivers) for scanning lines and data lines are formed on a substrate, and a liquid-crystal display device using the substrate. Such an active matrix substrate is produced using low-temperature polysilicon techniques, for example. In order to sell the products, which use the above active matrix substrate, on the market, it is necessary to accurately perform a testing of good or bad products from the perspective of guaranteeing reliability prior to the panel assembly after the substrate is formed.
According to a study conducted by the present inventor, the above-described inspection mainly requires basic inspections, such as checking the drivers' output ability and detecting a disconnection of the data lines, and inspections of the characteristics of switching devices (TFTs, MIMs, etc.) included in pixels as well as the leak characteristics of storage capacitors, which relate to an inspection on a point defect in an active matrix unit.
In the case of a digital driver for driving the data lines (namely, digital-data-line driver), a method for performing simultaneous driving at predetermined timing (line-at-a-time driving method) has been employed by paying attention to the ease of digital data storing.
A display device with such built-in digital-line-at-a-time-driving driver has not been realized, so that the manner in which the above-described highly reliable inspections are performed is not clear.